[PATCH v1 2/3] platform: arm64: thinkpad-t14s-ec: Wire EC thermal events to hwmon

[Daniel Lezcano]

The EC generates thermal zone status change notifications for a subset
of the exposed temperature sensors. Wire these EC events to the hwmon
notification framework so userspace can be informed when a thermal alarm
state changes.

Associate each hwmon temperature channel with its corresponding EC
thermal event and emit hwmon_temp_alarm notifications through
hwmon_notify_event() when the EC reports a thermal zone status change.

Also register thermal zones in the hwmon chip capabilities and keep a
reference to the hwmon device to allow event propagation from the IRQ
handler.

This allows userspace monitoring tools to receive thermal alarm
updates without polling the sensors and gives the opportuniy to the
kernel to cool them down.

Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxxxxxxxx>
---
 drivers/platform/arm64/lenovo-thinkpad-t14s.c | 66 ++++++++++++++-----
 1 file changed, 51 insertions(+), 15 deletions(-)

diff --git a/drivers/platform/arm64/lenovo-thinkpad-t14s.c b/drivers/platform/arm64/lenovo-thinkpad-t14s.c
index 142464623f0e..276bb51da33a 100644
--- a/drivers/platform/arm64/lenovo-thinkpad-t14s.c
+++ b/drivers/platform/arm64/lenovo-thinkpad-t14s.c
@@ -107,10 +107,13 @@ struct t14s_ec_led_classdev {
 struct t14s_ec_hwmon_sys_thermx {
 	const char *label;
 	int reg;
+	u8 event;
 };
 
 struct t14s_ec_hwmon {
+	struct device *dev;
 	struct t14s_ec_hwmon_sys_thermx *sys_thermx;
+	size_t num_sys_thermx;
 };
 
 struct t14s_ec {
@@ -493,6 +496,20 @@ static int t14s_input_probe(struct t14s_ec *ec)
 	return input_register_device(ec->inputdev);
 }
 
+static void t14s_ec_hwmon_notify_event(struct t14s_ec *ec, u8 event)
+{
+	for (int i = 0; i < ec->ec_hwmon.num_sys_thermx; i++) {
+		if (ec->ec_hwmon.sys_thermx[i].event != event)
+			continue;
+
+		hwmon_notify_event(ec->ec_hwmon.dev, hwmon_temp,
+				   hwmon_temp_alarm, i);
+
+		dev_dbg(ec->dev, "Thermal Zone (%s) Status Change Event\n",
+			ec->ec_hwmon.sys_thermx[i].label);
+	}
+}
+
 static irqreturn_t t14s_ec_irq_handler(int irq, void *data)
 {
 	struct t14s_ec *ec = data;
@@ -542,13 +559,9 @@ static irqreturn_t t14s_ec_irq_handler(int irq, void *data)
 		dev_dbg(ec->dev, "LID closed\n");
 		break;
 	case T14S_EC_EVT_THERMAL_TZ40:
-		dev_dbg(ec->dev, "Thermal Zone 40 Status Change Event (CPU/GPU)\n");
-		break;
 	case T14S_EC_EVT_THERMAL_TZ42:
-		dev_dbg(ec->dev, "Thermal Zone 42 Status Change Event (Battery)\n");
-		break;
 	case T14S_EC_EVT_THERMAL_TZ39:
-		dev_dbg(ec->dev, "Thermal Zone 39 Status Change Event (CPU/GPU)\n");
+		t14s_ec_hwmon_notify_event(ec, val);
 		break;
 	case T14S_EC_EVT_KEY_FN_G:
 		dev_dbg(ec->dev, "FN + G - toggle double-tapping\n");
@@ -658,6 +671,7 @@ static const struct hwmon_ops t14s_ec_hwmon_ops = {
 };
 
 static const struct hwmon_channel_info *t14s_ec_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_LABEL,
@@ -676,14 +690,34 @@ static const struct hwmon_chip_info t14s_ec_chip_info = {
 
 static int t14s_ec_hwmon_probe(struct t14s_ec *ec)
 {
-	struct device *dev;
 	struct t14s_ec_hwmon_sys_thermx sys_thermx[] = {
-		{ T14S_EC_SYS_THERM0, "soc" },
-		{ T14S_EC_SYS_THERM1, "keyboard" },
-		{ T14S_EC_SYS_THERM2, "base" },
-		{ T14S_EC_SYS_THERM3, "pmbm" },
-		{ T14S_EC_SYS_THERM6, "qtm" },
-		{ T14S_EC_SYS_THERM7, "ssd" },
+		{
+			.label = "soc",
+			.reg = T14S_EC_SYS_THERM0,
+			.event = T14S_EC_EVT_THERMAL_TZ39
+		},
+		{
+			.label = "keyboard",
+			.reg = T14S_EC_SYS_THERM1,
+			.event = T14S_EC_EVT_THERMAL_TZ40
+		},
+		{
+			.label = "base",
+			.reg = T14S_EC_SYS_THERM2,
+		},
+		{
+			.label = "pmbm",
+			.reg = T14S_EC_SYS_THERM3,
+			.event = T14S_EC_EVT_THERMAL_TZ42
+		},
+		{
+			.label = "qtm",
+			.reg = T14S_EC_SYS_THERM6
+		},
+		{
+			.label = "ssd",
+			.reg = T14S_EC_SYS_THERM7
+		},
 	};
 
 	ec->ec_hwmon.sys_thermx = devm_kmemdup_array(ec->dev, sys_thermx,
@@ -692,10 +726,12 @@ static int t14s_ec_hwmon_probe(struct t14s_ec *ec)
 	if (!ec->ec_hwmon.sys_thermx)
 		return -ENOMEM;
 
-	dev = devm_hwmon_device_register_with_info(ec->dev, "t14s_ec", ec,
-						   &t14s_ec_chip_info, NULL);
+	ec->ec_hwmon.num_sys_thermx = ARRAY_SIZE(sys_thermx);
+
+	ec->ec_hwmon.dev = devm_hwmon_device_register_with_info(ec->dev, "t14s_ec", ec,
+								&t14s_ec_chip_info, NULL);
 
-	return PTR_ERR_OR_ZERO(dev);
+	return PTR_ERR_OR_ZERO(ec->ec_hwmon.dev);
 }
 
 static int t14s_ec_probe(struct i2c_client *client)
-- 
2.53.0